I found no other meaningful solution besides hood cover. Just a piece of tarp works fine. Hood is the main area that needs protection from cats. While they might visit the other parts of the car as well, most of the damage they do is concentrated on the hood. And an non-groomed cat can easily do a lot of damage to the car's clearcoat with its claws.

The problem with a full car cover is that it is too cumbersome to put on and take off, which typically makes the owner to stop using it after a short while. Meanwhile a hood cover, sized precisely to cover the hood alone takes only about 30 seconds to put on or take off.

Granted, if you have a lot of abrasive particles collected on your hood, then a piece of tarp will not provide full protection, since a cat walking over the tarp will still cause the clearcoat to get scratched by those particles. However, it is still much better than what a cat can do to a completely unprotected clearcoat with its paws and claws.